Pond Boss Forums FISH & FISHING Sunfish-Including Largemouth and Smallmouth Bass What disease is this?

Scientists from the Australian Institute of Marine Science were near the Great Barrier Reef conducting a survey of shark prey, predominantly coral trout. They kept seeing strange dark patches on the normally bright orange fish, and for help they turned to another research team from the University of Newcastle in England that was studying coral disease in the area.

Sweet and his colleagues cut the fish tissue into slices and put them under a microscope. "We basically stumbled onto these tumor formations," he said. Then they compared them with samples from fish that had been given melanoma — the most dangerous type of skin cancer — as part of a laboratory experiment. They looked nearly identical.

The findings were published online Wednesday by the journal PLoS One.

Aside from their skin lesions, the fish that were captured by researchers did not show any signs of illness. But Nancy Knowlton, a marine ecologist at the Smithsonian Institution in Washington, said it remained possible that a significant number of fish were becoming sick from the cancer.

"Once the melanoma gets invasive, the fish probably get compromised," making them more vulnerable to sharks, said Knowlton, who was not involved in the study. "Somebody with advanced melanoma is being taken care of by doctors and loved ones, but fish will be eliminated fairly quickly."

"The individuals we looked at had extensive — but only surface — melanomas," Sweet said. "This means the cancer had not spread any deeper than the skin, so apart from the surface lesions, the fish were basically healthy."

"The individuals we looked at had extensive — but only surface — melanomas," Sweet said. "This means the cancer had not spread any deeper than the skin, so apart from the surface lesions, the fish were basically healthy."